Monday, 9 January 2012

What Are Stem Cells

Stem Cells are biological cells found in all multicellular organisms.  They can divide (mitosis) and differentiate into diverse and specialized cell types and can self-renew to produce more stem cells.  There are two types of stem cells, embryonic stem cells (found in the inner cell mass of a blatocyst, or early stage embryos) and adult stem cells, which are found in the tissues of adult humans.  There is also a third category of stem cells, Amniotic which are multipotent stem cells found in the afterbirth or placenta during child birth. In short, stem cells act as a repair system for the human body, replenishing adult tissues.

There are three sources of adult stem cells:
- Bone Marrow (which requires harvesting by drilling directly into the bone mass)
-Adipose Tissue (lipid cells, which require extraction by liposuction)
-Blood (which requires extraction by pheresis, or drawing blood)

Embryonic stem cells are cultures of cells derived from the epiblast tissue of the inner cell mass of a blastocyst, or early stage embryos.  Due to the nature of Embryonic stem cells, they provide the most promise in regenerative medical research as then can develop in to more than 200 cell types of the adult body when properly used.  However, there are a variety of moral and legal questions surrounding the use of Embryonic stem cells, specifically the quasi religous argument that human life begins at conception.  As such, there are currently no approved treatments using embryonic stem cells at this time.

Amniotic Stem Cells are retrieved from the the remaining amniotic fluid found in afterbirth and a childs umbilical cord.  These stem cells are very active and expand extensively with little intervention.  Amniotic stem cells are considered multipotent, meaning they can be used in a variety of medical procedures to great effect.  Use of stem cells from amniotic fluid bypasses ethical objections to using human embryos as the source of stem cells.  

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